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///////////////////////////////////////////////////////////////////////////////
//
// MODULE:        G4SPSEneDistribution.hh
//
// Version:      1.0
// Date:         5/02/04
// Author:       Fan Lei 
// Organisation: QinetiQ ltd.
// Customer:     ESA/ESTEC
//
///////////////////////////////////////////////////////////////////////////////
//
// CHANGE HISTORY
// --------------
//
//
// Version 1.0, 05/02/2004, Fan Lei, Created.
//    Based on the G4GeneralParticleSource class in Geant4 v6.0
//
///////////////////////////////////////////////////////////////////////////////
//
//
// Class Description:
//
// To generate the energy of a primary vertex according to the defined distribution 
//
///////////////////////////////////////////////////////////////////////////////
//
// MEMBER FUNCTIONS
// ----------------
//
// G4SPSEneDistribution ()
//    Constructor: Initializes variables
//
// ~G4SPSEneDistribution ()
//    Destructor: 
//
// void SetEnergyDisType(G4String)
//    Allows the user to choose the energy distribution type. The arguments
//    are Mono (mono-energetic), Lin (linear), Pow (power-law), Exp 
//    (exponential), Gauss (gaussian), Brem (bremsstrahlung), BBody (black-body), Cdg
//    (cosmic diffuse gamma-ray), User (user-defined), Arb (arbitrary
//    point-wise), Epn (energy per nucleon).
//
// void SetEmin(G4double)
//    Sets the minimum energy.
//
// void SetEmax(G4double)
//    Sets the maximum energy.
//
// void SetMonoEnergy(G4double)
//    Sets energy for mono-energetic distribution.
//
// void SetAlpha(G4double)
//    Sets alpha for a power-law distribution.
//
// void SetTemp(G4double)
//    Sets Temperature for a Brem or BBody distributions.
//
// void SetEzero(G4double)
//    Sets Ezero for an exponential distribution.
//
// void SetGradient(G4double)
//    Sets gradient for a linear distribution.
//
// void SetInterCept(G4double)
//    Sets intercept for a linear distribution.
//
// void UserEnergyHisto(G4ThreeVector)
//    Allows user to defined a histogram for the energy distribution.
//
// void ArbEnergyHisto(G4ThreeVector)
//    Allows the user to define an Arbitrary set of points for the
//    energy distribution.
//
// void EpnEnergyHisto(G4ThreeVector)
//    Allows the user to define an Energy per nucleon histogram.
//
// void Calculate()
//    Controls the calculation of Integral PDF for the Cdg and BBody
//    distributions.
//
// void InputEnergySpectra(G4bool)
//    Allows the user to choose between momentum and energy histograms
//    for user-defined histograms and arbitrary point-wise spectr.
//    The default is true (energy).
//
// void InputDifferentialSpectra(G4bool)
//    Allows the user to choose between integral and differential 
//    distributions when using the arbitrary point-wise option.
//
// void ArbInterpolate(G4String)
//    ArbInterpolate allows the user to specify the type of function to
//    interpolate the Arbitrary points spectrum with.
//
//  void SetBiasRndm (G4SPSRandomGenerator* a)
//    Sets the biased random number generator
//
//  G4double GenerateOne(G4ParticleDefinition*);
//    Generate one random energy for the specified particle
//
//  void ReSetHist(G4String);
//    Re-sets the histogram for user defined distribution
//
// void SetVerbosity(G4int)
//    Sets the verbosity level.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef G4SPSEneDistribution_h
#define G4SPSEneDistribution_h 1

#include "G4PhysicsOrderedFreeVector.hh"
#include "G4ParticleMomentum.hh"
#include "G4ParticleDefinition.hh"
#include "G4DataInterpolation.hh"

//
#include "G4SPSRandomGenerator.hh"

class G4SPSEneDistribution
{
public:
  G4SPSEneDistribution (); 
  ~G4SPSEneDistribution ();

  void SetEnergyDisType(G4String);
  inline G4String GetEnergyDisType() {return EnergyDisType;};
  void SetEmin(G4double);
  inline G4double GetEmin() {return Emin;} ;
  inline G4double GetArbEmin() {return ArbEmin;} ;
  void SetEmax(G4double);
  inline G4double GetEmax() {return Emax;} ;
  inline G4double GetArbEmax() {return ArbEmax;};
  void SetMonoEnergy(G4double);
  void SetAlpha(G4double);
  void SetTemp(G4double);
  void SetBeamSigmaInE(G4double);
  void SetEzero(G4double);
  void SetGradient(G4double);
  void SetInterCept(G4double);
  void UserEnergyHisto(G4ThreeVector);
  void ArbEnergyHisto(G4ThreeVector);
  void EpnEnergyHisto(G4ThreeVector);

  void InputEnergySpectra(G4bool);
  void InputDifferentialSpectra(G4bool);
  void ArbInterpolate(G4String);
  inline G4String GetIntType() {return IntType;};
  void Calculate();
  //
  void SetBiasRndm(G4SPSRandomGenerator* a) {eneRndm = a; };
  // method to re-set the histograms
  void ReSetHist(G4String);
  // Set the verbosity level.
  void SetVerbosity(G4int a) {verbosityLevel = a; } ;
  //x
  G4double GenerateOne(G4ParticleDefinition*);
  
private:
  void LinearInterpolation();
  void LogInterpolation();
  void ExpInterpolation();
  void SplineInterpolation();
  void CalculateCdgSpectrum(); 
  void CalculateBbodySpectrum();

  // The following methods generate energies according to the spectral
  // parameters defined above.
  void GenerateMonoEnergetic();
  void GenerateLinearEnergies(G4bool);
  void GeneratePowEnergies(G4bool);
  void GenerateExpEnergies(G4bool );
  void GenerateGaussEnergies();
  void GenerateBremEnergies();
  void GenerateBbodyEnergies();
  void GenerateCdgEnergies();
  void GenUserHistEnergies();
  void GenEpnHistEnergies();
  void GenArbPointEnergies();
  // converts energy per nucleon to energy.
  void ConvertEPNToEnergy();

private:

  G4String EnergyDisType; // energy dis type Variable  - Mono,Lin,Exp,etc
  G4double MonoEnergy; //Mono-energteic energy
  G4double SE ; // Standard deviation for Gaussion distrbution in energy
  G4double Emin, Emax; // emin and emax
  G4double alpha, Ezero, Temp; // alpha (pow), E0 (exp) and Temp (bbody,brem)
  G4double grad, cept; // gradient and intercept for linear spectra
  G4bool EnergySpec; // true - energy spectra, false - momentum spectra
  G4bool DiffSpec;  // true - differential spec, false integral spec
  G4bool ApplyRig; // false no rigidity cutoff, true then apply one
  G4double ERig; // energy of rigidity cutoff
  G4PhysicsOrderedFreeVector UDefEnergyH; // energy hist data
  G4PhysicsOrderedFreeVector IPDFEnergyH;  
  G4bool IPDFEnergyExist, IPDFArbExist, Epnflag;
  G4PhysicsOrderedFreeVector ArbEnergyH; // Arb x,y histogram
  G4PhysicsOrderedFreeVector IPDFArbEnergyH; // IPDF for Arb
  G4PhysicsOrderedFreeVector EpnEnergyH; 
  G4double CDGhist[3]; // cumulative histo for cdg
  G4double BBHist[10001], Bbody_x[10001];
  G4String IntType; // Interpolation type
  G4double Arb_grad[1024], Arb_cept[1024]; // grad and cept for 1024 segments
  G4double Arb_alpha[1024], Arb_Const[1024]; // alpha and constants
  G4double Arb_ezero[1024]; // ezero
  G4double ArbEmin, ArbEmax; // Emin and Emax for the whole arb distribution used primarily for debug.

  G4double               particle_energy;
  G4ParticleDefinition*  particle_definition;

  G4SPSRandomGenerator* eneRndm;

  // Verbosity
  G4int verbosityLevel;

  G4PhysicsOrderedFreeVector ZeroPhysVector ; // for re-set only 

  G4DataInterpolation *SplineInt; // holds Spline stuff

};


#endif